1. Field of the Invention
The present invention relates to a storage box such as a glovebox, an instrument panel upper box and a console box.
2. Description of the Related Art
A glovebox of an automobile is opened or closed by a glovebox door which is turnably held by an instrument panel. Automotive gloveboxes of recent years often employ an integral structure of a storage portion and a glovebox door. Such a glovebox is produced by assembling an outer panel having a designed surface and formed of resin, and an inner panel having a storage portion and formed of resin.
Conventionally the outer panel and the inner panel have been combined to ether by screws, but this assemble method has an aesthetic problem in that when the glovebox door is open, heads of the screws are seen. This assemble method has another problem in that worker-hours for an assembling operation increase because the screws have to be fastened at a plurality of locations.
Therefore, these days, vibration welding is employed to combine the outer panel and the inner panel as described in Japanese Unexamined Patent Publication No. 2010-111306.
Vibration welding is a welding process of bringing a pair of members to be combined in contact under an applied load and vibrating one of the members so as to generate heat by friction and weld fore ends of welding ribs or others of the one of the members to a welding surface of the other of the members. Therefore, in order to uniformly transmit force of pressure to the respective welding ribs, projecting directions of the respective welding ribs need to be in parallel to a pressure direction.
In a case of such an automotive interior part having a greatly curved designed surface as a glovebox door, however, if the projecting directions of the respective welding ribs are set in parallel to the pressure direction, angles of the respective welding ribs with respect to a surface of the mating member to be welded vary by area, and some welding ribs forming small angles with the surface are liable to fall down toward an acute angle side. Hence, the pressure force is not uniformly transmitted to the respective welding ribs, and the welding ribs are not uniformly welded to the surface. This sometimes causes a blemish in designed appearance such as highlighted portions.
In these circumstances, Japanese Unexamined Patent Publication NO. 2011-073469 has proposed a glovebox door comprising an inner panel having an inner surface on which a plurality of welding projections are formed in a manner to project in a direction of pressure applied for vibration welding, and an outer panel having an inner surface including a first surface and a second surface whose cross section tangent lines intersect with each other, wherein at least one of the first surface and the second surface has a receiving flat surface which faces to a fore end of one of the welding projections and extends in a perpendicular direction to the direction of the pressure applied for the vibration welding, and the fore end of the welding projection is welded to the receiving flat surface.
Even if this glovebox door has a greatly curved designed surface, all the welding projections can be uniformly welded and a blemish in designed appearance and other problems can be prevented beforehand.
However, therein en inevitable variation in welding precision in vibration welding. Even the structure of PTL 2 has a problem in that a large number of worker-hours are necessary for production preparations. The vibration welding has another problem in that large-scale equipment is necessary and production plants are limited.